Driven spinning top

ABSTRACT

A modified classical spinning top ( 1 ) and its horizontal driving ( 6 ) without mechanical restraining elements are disclosed. The modified classical spinning top has a small permanent magnet ( 2 ) on the rotation axis ( 3 ), at its upper part and coaxial with it. A second permanent magnet ( 4 ) with the opposite polarity to the first one, it means in an attraction configuration, is manually moved horizontally ( 7 ) above the top of the spinning top. The interaction of attraction of the two permanent magnets determines a horizontal driving ( 6 ) of the spinning top without modification of the rotation movement. The new toy is more interesting, interactive and attractive than the classical one.

FIELD OF INVENTION

The present invention relates to a modified classical spinning top (using permanent magnets and no mechanical restraints) that can be horizontally driven without the modification of the rotation movement.

BACKGROUND OF THE INVENTION

It is well known that people like the classical toys: spinning tops, gyroscopes and permanent magnets.

Spinning tops are old toys. They are built from wood, metals, or plastics in different shapes, colors and dimensions. Recently some of them produce a sound or/and light. Not much has been changed since the beginning. Once it is put into rotation we just look at its movement. No possibility to change the movement, to interact with it.

Gyroscopes are well known toys and devices. They fascinate how the direction is kept constant.

Permanent magnets are used to obtain different configurations using balls, nails, ferromagnetic powder, magnetic fluids. Once the configuration is achieved nothing can happen more, no more fun.

The idea of combining the rotation movement of a gyroscope and permanent magnets has been advanced by I. Grosu in Romania Patent No. 91 857 from 28 Feb. 1987. A classical gyroscope is modified by using two permanent magnets on the rotation axis, coaxial with it. So the gyroscope has an angular momentum and a magnetic moment. A uniform external magnetic field generated by a coil determines a rotation that is the Larmor precession. This device is didactic and can show how the Larmor precession is obtained. Such a gyroscope simulates the spin of the electron with angular momentum and magnetic moment.

An interesting use of permanent magnets in spinning tops is the Levitron: U.S. Pat. No. 4,382,245 and U.S. Pat. No. 5,404,062. The disk of the spinning top is a permanent magnet above a second permanent magnet in the repulsion configuration. The spinning top can levitate if some conditions are fulfilled. The levitation is not so easy to be obtained. Levitron is produced by: www.supermagnete.de.

Another toy—Magnetic UFO Spinning Top—has a small permanent magnet at the bottom that is in contact with a ferromagnetic planar piece. During rotation the bottom of the spinning top moves the planar piece in an interesting manner.

Using the site www.espacenet.com with the keywords toy AND top AND magnet there are selected the patents: US 2004198152, US 2003064660, GB2389321, CN1326800 that presents tops with permanent magnets. It should be emphasized that all patents refer to tops with uncontrollable dynamics.

SUMMARY OF THE INVENTION

The present invention is directed to a spinning top with a controllable horizontal motion. The dynamics of the classical spinning top can not be changed because any action on it is equivalent with a torque N that will modify the rotation motion according to the angular momentum theorem:

dL/dt=N

where L, N are the angular momentum and torque respectively. To move the top horizontally it is necessary to act on it with a force that passes the rotation axis (to have a torque equal with zero). This can be realized by the interaction of attraction of the two permanent magnets; one on the axis of rotation, coaxial with it and another one above the top. Everything will be better understood following the drawings, detailed description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. A general view of the modified spinning top.

FIG. 2. Detailed view of the permanent magnet at the upper part of the top

FIG. 3. The collision of two cylindrical shaped tops.

FIG. 4. The suspended top into rotation.

FIG. 5. The collision between two tops: one with a hexagonal shape and another one with a cylindrical shape.

FIG. 6. The collision between a top with a hexagonal shape and a ball.

DETAILED DESCRIPTION OF THE INVENTION

As it was mentioned above all combinations top and permanent magnets did not achieve a controllable dynamics for tops. The dynamics of a modified gyroscope (I. Grosu, Romania Patent No. 91 857) is controllable by using an external magnetic field. This idea, in a modified version, is used here. The key idea is to modify a classical spinning top by using a permanent magnet on the rotation axis, at its upper part, coaxial with it. An external permanent magnet, manually moved above the top, attracts the first magnet moving the top horizontally. The rotation motion is not changed because the torque of the attraction force between two permanent magnets is zero. This happens because the direction of this force passes the rotation axis. So the horizontal translation motion of the top can be controlled by the motion of the external permanent magnet. The top with a controllable dynamics has much more interest and fun and educational and scientific achievements.

Following FIG. 1 and FIG. 2 a classical spinning top 1 is modified by using a small permanent magnet 2 on the rotation axis 3, coaxial with it, at its upper part. A second permanent magnet 4 is above the top into rotation 5. The top moves horizontally 6 following the horizontal motion 7 of the permanent magnet 4. The motion 6 is obtained only if the motion 7 is slow. At rapid movement 7 the top is not able to follow it.

The top with controllable dynamics can be used to realize several games. I propose here 3 variants.

First one refers to the dynamics of the top. It can be experimented how quick should be the motion 7 in order to obtain a movement 6. A too quick move 7 fails to obtain a movement 6. Two tops can collide 8 when they are close enough (FIG. 3). It is interesting that after the collision they can collide again because of the Bernoulli law. Also if the permanent magnet 4 is close enough then the top jumps in contact with it. The rotation continues. (FIG. 4). If the magnet 4 is vertically shaken the top falls on the table on the table and continues to rotate and it can be attracted again to magnet 4. Here can be observed how the vertical direction is conserved. This can not be done with the classical spinning top.

Secondly a collision can be obtained between a hexagonal shaped top 9 and a cylindrical shaped one 1 (FIG. 5). Here the collision is more violent because of the shape of the hexagonal shaped top 9.

Thirdly a competition game can be realized by using a hexagonal shaped top 9 and a ball 10. The ball 10 moves horizontally. Two players each having a hexagonal shaped top 9 hit the ball (FIG. 6) in order to move it in the others gate. I call this game TOPBALL in analogy with football, handball, basketball.

Others games can be imagined using the driven spinning top with a controllable dynamics.

REFERENCES

-   1. I. Grosu, “Didactic device for obtaining Larmor precession” (in     Romanian), Romania Patent Nr. 91857/28 Feb. 1987, Application nr.     118 306/08 April 1985 -   2. Sonia and Roger Kaysel (1991), “Kreisel”, Schweizer Kindermuseum     Baden, Switzerland. -   3. R. M. Harrigan (1983), “Levitation device”, U.S. Pat. No.     4,382,245, May 3, 1983 -   4. E. W. Hones and W. G. Hones, “Magnetic Levitation Device and     Method” U.S. Pat. No. 5,404,062 -   5. H. Goldstein, “Classical Mechanics” Addison-Wesley, 1965, p. 3 -   6. P. A. Tipler (1991), “Physics for Engineers and Scientists”,     3^(rd) Edition, Vol. 2, p. 798-800, Worths Publishers. -   7. F. W. Sears, M. W. Zemansky and H. D. Young (1987), “University     Physics” 7^(th) Edition, p. 698-700, 1987 -   8. R. Holler, “Kreisel”, H. Hugedubel Verlag, 1989 

1. I claim that using the last generation of commercially available permanent magnets (based on Neodimium with small dimensions and strong interactions at distances up to 40 mm) a horizontally driven spinning top can be realized. The horizontal driving is more than 5 mm/sec and up to 15 mm/sec in a desired direction without any mechanical contact.
 2. The said driven spinning top uses the interaction between a small permanent magnet on the rotation axis, at its upper end a second bigger permanent magnet manually moved horizontally above the top of the spinning top at a distance more than 10 mm and up to 40 mm. We call this configuration two permanent magnets configuration.
 3. In the said two permanent magnets configuration it is essential to be used two permanent magnets and not a permanent magnet and a magnetizable body. In the second case the interaction is noticeable at much smaller distances and the driving is hard or impossible to be obtained because the two bodies stick together (pick up) ending the horizontal driving.
 4. The magnets of claim 1, wherein said driven spinning top, using the said two permanent magnets configuration is interactive and has a richer dynamics (possible with a chaotic component) that rises the interest for fun and curiosity and educational and didactic and scientific investigation at different levels of understanding of different ages; the new dynamics should be deeply investigated both experimentally and theoretically by using numerical methods for solving the equations of motion adapted to the new said two permanent magnets configuration. 